WO 2009/040725 A2 discloses a lighting device for vehicles having a laser light source for generating a light beam. In order to create an incoherent light source that emits a relatively homogeneous beam of light, the well-known lighting device provides a light conducting device for the conversion of the light beam emitted by the laser light source into a light bundle. The light conducting device comprises a cylindrical transparent fiber material, on whose end faces are arranged mirrors. On the circumference, the fiber material is provided with a coating with scattering effect. A disadvantage of the known lighting device is that it has a relatively large volume.
Heretofore, incandescent lamps, halogen lamps, or LED light sources have been mostly used in vehicles for the functions of a signal light. LED light sources have a relatively small dimension, which can produce different lighting functions with appropriate light conducting devices such as fiber optics or reflectors. To generate a rear fog light function, usually multiple LED light sources are used, because the control effort would be too great when using a single LED light source due to the luminous flux variations. In this respect, the dimension of the lighting device with the use of LED light sources can be reduced in many cases only to a certain extent. A reduction of the dimension of the lighting device has limits to the extent as for a rear fog light function a minimum distance to a stoplight function must be always maintained. Against this background that for designing reasons the lights must increasingly have a smaller dimension, the integration of a rear fog light in a housing of a lighting device, which is to radiate more light functions, becomes more and more difficult.